Aeronautical propeller



April 25, 3 w. J. BLANCHARD 1,905,891

Y AERONAUTKML PROPELLER Filed July 14, 19:50

(F161. FIGZ.

INVENTOR Patented Apr. 25, 1933 UNITED STATES PATENT OFFICE" WERNER J'.BLANGHARD, OF HEMPSTEAD, NEW YORK, ASSIGNOR '10 QURTISS AERO- PLANE GaMOTOR COMIPANY, INC A CORPORATION OF NEW YORK AERONAUTICAL PROPEILERApplicationflled July 14,,1930. Serial No. 467,732.

My invention relates to aeronautical propellers and more particularly toone piece forged metal aeronautical propellers having thin solid bladesand integral therewlth a central boss or hub forming enlargement.

The object of the invention is to so form and construct a one pieceforged metal aeronautical propeller, as to secure unusual strength,minimum weight, uniformity of metal distribution, and decreasedmanufacturing cost.

Strength.--Maximum strength is obtained by reason of the fact that thetensile forces at or near the hub portion of the 1 propeller, instead ofacting-at an angle to the longitudinal axis of the propeller blades,

acts in substantially a straight line and in parallelism with said axis.That this may,

be accomplished, the opposed blades, at or near said hub portion,instead of being formed in or twisted to out-of-alignment relation, liein substantially the same plane and are of substantially uniformthickness and width even at their point of juncture with said hubforming enlargement.

Weight.The weight of the propeller is approximately twenty percent lessthan its contemporaries. Reduction is achieved by the economicaldistribution of metal at ornear the hub, as Well as by the completeelimination of that bulk of metal at or near the hub heretoforeconsidered essential,

Uniformity of metal Through a more uniform and hence better distributionof the metal, a smoother running propeller is made possible and theimaging operation very materially simpli- Decreased manufacturing00st.Production or manufacturing cost is lessened (a) by the eliminationof metal bulk, (b) by a simplification of the forging operation and (0)by the elimination of the heretofore required and separately obtainedtwisting of the propeller blades. In the present invention, thepropeller, instead of bein forged in the rough and thereafter twisted,is forged with the blades twisted or rather pitched to the requiredangle. Only the 50 finishing operation, i. e., filing and polish- -1010and a central integral hub forming distributiowing,.is left undone bythe forging operation.

By the substantial decrease in production cost made possible in themanner indicated, plus the elimination of metal bulk, it is now possibleto manufacture and sell, at a reasonable profit, solid forged metalpropellers, in competition with wooden propellers of similar size ordimension. Since it is an established fact that metal propellers havingthin and solid blades are more efficient than the corresponding types ofwooden propellers, obviously a step in the right direction in theadvancement of the art of propeller manufacturing has been accomplished.

In the drawing, wherein like reference characters denote like orcorresponding parts,

Fig. 1 is a face view of the propeller, and

Fig. 2 is an edge view or side elevation.

The propeller, as intimated, is of metal, preferably of an alloy ofaluminum, such as duralumin, and is forged in one piece, and except forthe filing and polishing, is completed in a single operation. As thetwoblade propeller is by far the most common,

this particular type of propeller has been selected for illustration.

The propeller comprises opposed (blades 89 enlargement 11. Theenlargement 11 is 5 formed by the provision of opposed bosses 1212 whichextend out from the opposite faces of the blades 10-10 at the line ofjuncture of the blades, each boss or enlargement extending axially ofthe propeller and being of substantially uniform outside diameter andpreferably substantially circular from end to end. In the interest ofthe elimination of metal bulk each boss or enlargement has an over-alldiameter substantially less than the over-all width of the blades attheir point of juncture. The enlargements 12l2, together with the midportions of the blades 1010, form a hub of substantial length foraccommodation on a. suitable propeller shaft. The hub thus formed ispreferably at least twice as long as the longitudinal depth or thicknessof the blades, to give an adequate mounting surface to assume torsionaland rocking stresses to Which the propeller is subject.

The blades 1010, for some little distance at opposite sides of the axisof rotation of the propeller, are directly opposed, each making (seeFig. 2) a straight line continuation of the other. In other words, inthe vicinity of the hub forming enlargement 11, the propeller blades areuntwisted and of almost uniform thickness and width. Thus constructed,the weight is reduced and at the same tlme the strength increased. By

" making one blade a strai ht line continuation of the other in thevicinity of the hub, the forces. acting thru the hub (where thepropeller is most heavily stressed) act in direct opposition and in .amanner such that better balance, a better distribution of metal bulk andsubstantially a twenty percent saving in weight is achieved. While it isapparent that in an aeronautical propeller the metalcannot bedistributed in true uniformity, itis nevertheless felt that in theresent embodiment, such a condition has, 25

en more nearly approached than in any ropeller heretofore designed orconstructed. oreover, by reason of the uniformdistribution of metal, theforging operat on is made easier and" a great deal more dependable, thuslessening the number of re'ections here'- tofore encountered in. themanu acture of on I all diameter not .portions of the and having asubstantially uniform overreater than the width of the propeller bla esat the line of juncture therebetween. I 3. A one iece metal aeronauticalpropeller comprising a pair of integral op o- .sitely extendingangularly' itched bla es, and a centrally disposed hu formingenlargement integral with said blades, the portions of the bladesadjacent the hub being untwisted and each being a straight linecontinuation of the other.

4. A one piece metal aeronautical propeller comprising a pluralit ofintegral radially extending angularly itched blades, and a centrallydisposed hub forming enlargement inte a1 with said blades, the

lades adjacent the hub being untwisted and lying in a common planenormal tothe axis of rotation of the propeller.

5. A one piece metal aeronautical propeller comprising a plurality ofintegral radially extendin angularly pitched blades, and a centrallyisposed hu largement inte tions of the b ades adjacent the hub beinguntwisted and lying in a common plane normal to the axis of rotation ofthe proeller, said inner. blade portions being oined one -to another bycontinuations thereof enclosing said hub portion.

In testimony whereof I hereunto afiix my signature.

WERNER J. BLANCHARD.

lntegral therewith and on opposite faces thereof opposed hub formingenlargements,

said enlargements, in each instance, being of circular section and ofsubstantially uniform diameter, the diameter, in each case, beingsubstantially less than the width of the propeller at the line of'uncture of the propeller blades, and the ength, in each case, beingsubstantially greater than the 2. A one piece forged metal aeronauticalI r0 ller comprisin thin solid 0 osed lad of substantiafily uniformthiizkness forming en.-. al with said blades, the por-

